1. Field of Invention
The present invention relates to a method for installing an electro-optical device such as a liquid crystal panel, CCD device, or a panel employing an illuminant, to a prism, such as a dichroic prism or a polarization beam splitter, and a manufacturing method for a projector that employs the foregoing method.
2. Description of Related Art
As a conventional method for installing an electro-optical device, such as a liquid crystal panel to a prism, there are methods whereby an electro-optical device is directly attached to a prism, or a method such as that disclosed in Japanese Unexamined Patent Publication No. 10-10994.
The technology disclosed in Japanese Unexamined Patent Publication No. 10-10994 will be briefly explained in conjunction with FIG. 13 and FIG. 14.
First, a liquid crystal panel unit 70R is installed to a light incident surface 72R of a prism composite 72 of a projector.
The panel unit 70R is formed of a fixing frame member 76 on an innermost side that is adhesively fixed to the light incident surface 72R of the prism composite 72, a panel frame assembly 73 on an outermost side that holds and retains a liquid crystal panel 80R, and an intermediate frame member 77 disposed between the fixing frame member 76 and the panel frame assembly 73. The panel frame assembly 73 has a first frame member 74 and a second frame member 75, the liquid crystal panel 80R being sandwiched between these frame members 74 and 75.
Engaging lugs 77b protuberantly provided outward at the four corners of the intermediate frame member 77 are adhesively fit in engaging holes 74b formed at the four corners (of the first frame member 74) of the panel frame assembly 73, and the intermediate frame member 77 and the panel frame assembly 73 are adhesively fixed with a spacer 78 which is shaped in a substantially triangular prism and installed between the intermediate frame member 77 and the panel frame assembly 73.
The configuration is accomplished by an installing method illustrated by a simplified flowchart in FIG. 14.
First, the fixing frame member 76 is positioned and adhesively fixed to the light incident surface 72R of the prism composite 72 (step S1 of FIG. 14). Then, the intermediate frame member 77 is positioned on the outer side of the fixing frame member 76, which has been adhesively fixed, and secured with four screws 79 by inserting them in tapped holes 77a and 76a (step S2 of FIG. 14).
After that, engaging holes 74b provided in the first frame member 74 of the panel frame assembly 73 holding and retaining the liquid crystal panel 80R are filled with an adhesive agent, then the engaging lugs 77b of the intermediate frame member 77 are fit in the engaging holes 74b thereby to mount the panel frame assembly 73 on the intermediate frame member 77 (step S3 of FIG. 14). The foregoing steps S1 through S3 constitute a panel mounting process.
Next, the liquid crystal panel 80R is lit under this condition (step S4 of FIG. 14) to perform focus adjustment and alignment adjustment of the liquid crystal panel 80R (steps S5 and S6 of FIG. 14). Steps S4 through S6 are carried out mainly to adjust the position or tilt of the liquid crystal panel 80R on or with respect to an optical axis. The foregoing steps S4 through S6 constitute a position adjustment process.
Then, the adhesive agent charged in the engaging holes 74b is hardened to temporarily fix the intermediate frame member 77 and the panel frame assembly 73 (step S7 of FIG. 14). After that, a displacement amount of the position of a pixel of the liquid crystal panel 80R is checked (step S8 of FIG. 14). As a result, if the displacement amount exceeds a permissible range (if the displacement is unacceptable), then the panel frame assembly 73 is detached (step S12 of FIG. 14) and returned to step S3 mentioned above. These steps S7 and S8 constitute a temporary fixing process.
If the displacement amount is within the permissible range (if the displacement amount is acceptable), then an adhesive agent is applied to the spacer 78 (step S9 of FIG. 14), and the spacer 78 is installed to a predetermined guiding portion formed between the preliminarily fixed intermediate frame member 77 and the panel frame assembly 73 (step S10 of FIG. 14).
Then, the adhesive agent between the spacer 78, the panel frame assembly 73, and the intermediate frame member 77 is hardened to firmly fix the panel frame assembly 73 to the prism composite 72 step S11 of FIG. 14). Steps S9 through S11 constitute a final fixing process.
According to the conventional method set forth above, however, there is a danger in that the liquid crystal panel is displaced in the final fixing process since the panel frame assembly is temporarily fixed after adjusting the position of the liquid crystal panel in relation to the prism, then the final fixing is performed at a different position from the position of the temporary fixing.
Furthermore, the temporary fixing process and the final fixing process respectively require time for hardening the adhesive agent, presenting poor operation efficiency and a complicated operation process because of different hardening positions.
In addition, the provision of the temporarily fixed portions results in many bonded locations which are susceptible to contraction that takes place when the adhesive agent hardens, frequently causing an error in the position of the liquid crystal panel.
Furthermore, since the temporary fixing and the final fixing are performed at different positions, it is very likely that the heat generated by a projector in operation causes the liquid crystal panel to be displaced. For this reason, there has been room for improvement in achieving a projector that remains free from displacement of a liquid crystal panel over an extended time of use.